Who says American politics is gridlocked? A tidal wave of politicians from both sides of the aisle who just a few years ago opposed same-sex marriage are now coming around to support it. Even if the Supreme Court were decide to do nothing about California’s Proposition 8 or DOMA, it would seem only matter of time before both were repealed.

A significant number of elected officials who had been against allowing undocumented immigrants to become American citizens is now talking about “charting a path” for them; a bipartisan group of senators is expected to present a draft bill April 8.

Even a few who were staunch gun advocates are now sounding more reasonable about background checks.

It’s nice to think logic and reason are finally catching up with our elected representatives, but the real explanation for these changes of heart is more prosaic: public opinion.

The latest ABC News/Washington Post poll finds support for marriage equality at the highest in the ten years the question has been asked, with 58% of Americans in favor and 36 percent opposed.

A similar swing has occurred in favor of immigration reform. A new Pew survey finds that seven-in-ten Americans (71%) say there should be a way for people in the United States illegally to remain in this country if they meet certain requirements, while 27% say they should not be allowed to stay legally. And most who favor providing illegal immigrants with some form of legal status –43% of the public – say they should be allowed to apply for citizenship.

Support for gun control is less clear-cut, which may explain why Senate Majority Leader Harry Reid won’t seek a renewal of the assault-weapon ban. But polls show broad support for universal background checks, and for closing the so-called gun-show loophole.

It’s possible that public opinion is being influenced by courageous political leaders who are urging action on these issues, but the reverse is more likely. Most politicians have a keen sense for tipping points in public opinion, when, say, support for equal marriage rights or immigration reform becomes broad-based, and advocates become sufficiently organized and mobilized to make life hell for officials who won’t change their minds.

The exception is in the economic sphere, where public opinion seems beside the point.

Before January’s fiscal cliff deal, for example, at least 60 percent of Americans, in poll after poll, expressed strong support for raising taxes on incomes over $250,000. As you recall, though, the deal locked in the Bush tax cut for everyone earning up to $400,000.

Yes, legislative deals require compromise. But why is it that deals over economic policy almost always compromise away what a majority of Americans want?

Most Americans weren’t particularly concerned about the budget deficit to begin with. They’ve been far more concerned about jobs and wages. Yet maneuvers over the deficit have consistently trumped jobs and wages. 

Recent polls show Americans would rather reduce the deficit by raising taxes than by cutting Medicare, Medicaid, Social Security, education, and transportation. Yet Congress seems incapable of making that kind of deal.

Some 65 percent of Americans want to raise taxes on large corporations — but both parties are heading in precisely the opposite direction.

Half of Americans favor a plan to break up Wall Street’s twelve megabanks, which currently control 69 percent of the banking industry. Only 23 percent oppose such a plan (27 percent are undecided).

You might this would at least prompt an examination of the possibility on Capitol Hill and the White House — especially now that the Street is actively eviscerating regulations under Dodd-Frank.   

But our elected representatives don’t want to touch Wall Street. According to Politico, even the White House believes too-big-to-fail will soon be a closed chapter.

Why are politicians so sensitive to public opinion on equal marriage rights, immigration, and guns – and so tone deaf to what most Americans want on the economy?

Perhaps because the former issues don’t threaten big money in America. But any tinkering with taxes or regulations sets off alarm bells in our nation’s finely-appointed dining rooms and board rooms – alarm bells that, in turn, set off promises of (or threats to withhold) large wads of campaign cash in the next election.

When political scientists Benjamin Page and Larry Bartels surveyed Chicagoans with an average net worth of $14 million, they found their biggest concern was curbing budget deficits and government spending – ranking these as priorities three times as often as they did unemployment.

And – no surprise — these wealthy individuals were also far less willing than are other Americans to curb deficits by raising taxes on high-income people, and more willing to cut Social Security and Medicare. They also opposed initiatives most other Americans favor — such as increasing spending on schools and raising the minimum wage above the poverty level.

The other thing distinguishing Page’s and Bartels’ wealthy respondents from the rest of America was their political influence.

Two-thirds of them had contributed money (averaging $4,633) in the most recent presidential election. A fifth of them had even “bundled” contributions from others.

That money bought the kind of political access most Americans only dream of. About half of these wealthy people had recently initiated contact with a U.S. senator or representative — and nearly half (44 percent) of those contacts concerned matters of relatively narrow economic self-interest rather than broader national concerns.

This is just the wealthy of one city — Chicago. Multiply it across the entire United States and you begin to see the larger picture of whom our representatives are listening to, and why. Nor does the survey include the institutionalized wealth – and economic clout – of Wall Street and large corporations. Multiply the multiplier.  

Great wealth can also influence public opinion. It is possible, for example, that the piles of money spent by billionaire Pete Peterson to persuade Americans that the budget deficit is the nation’s most urgent economic problem is now paying off. Recent polls show greater concern about the deficit now than was expressed a few years ago when the deficit represented a much larger percentage of the total economy.

It is good that politicians are exquisitely sensitive to shifts in public opinion on issues like same-sex marriage, undocumented immigrants, and guns. This is a feature of our democracy worth celebrating.

But American democracy has shown itself far less responsive – and our politicians remarkably impervious – to public opinion concerning economic issues that might affect the fates of large fortunes. This is a distressing feature of our democracy, necessitating change.